Method of making dipentene and vinylcyclohexene resin



Patented Sept. 18, 1951 METHOD OF MAKING DIPENTENE AND VINYLCYCLOHEXENE RESIN Samuel G. Burroughs, Pittsburgh, Pa., assignor to Pennsylvania Industrial Chemical Corporation, Clairton, Pa., a corporation of Pennsylvania No Drawing. Application August 23, 1948, Serial No. 45,781

7 Claims.

This invention relates to a resin composed of mixed vinyl cyclohexene and dipentene polymers substances. This impure, approximately 85% vinyl cyclohexene polymerizes under the influence of aluminum chloride and related acid-reacting metal halide catalysts very slowly and incompletely to form two types of resin, one of which has a melting point of about 100 and is soluble in mineral spirits at normal room temperature, and the other of which is lnfusible and is insoluble in all commonly used organic solvents. These two types of resin are formed approximately simultaneously and separate from each other with precipitation of the insoluble type. Because of poor yield and the impossibility of directing the polymerization reaction, the impure cyclohexene is to be considered valueless as a starting material for the production of resin of either type. I have, however, found that by purifying the vinyl cyclohexene and by subjecting it to polymerization in association with dipentene, I am able to obtain good yields of solid resins.

Any suitable purification procedure may be followed to obtain an approximately pure vinyl cyclohexene starting material. One specific procedure which I have advantageously followed is to wash the impure vinyl cyclohexene by-product wih 59 Baum sulphuric acid (74%) at C. The product of the purification consists of about 90% pure vinyl cyclohexene responding apparently to the formula This acid washed vinyl cyclohexene has a specific gravity of 0.8336 at 155 C., a boiling range of 125 C. to 131 C., a bromine number of 280, and a refractive index of 1.464 at 20 C. This material when diluted with a hydrocarbon diluent, such as toluol, and subjected to a polymerization re- 3 action with aluminum chloride, or its substantial equivalent as a catalyst, gives a yield of about 80% of infusible insoluble resin. and about a 20% yield of resin having a melting point of 80 C. (ball and ring) which is soluble in mineral spirits at normal room temperature. There is greatdiversity in the properties of the diverse types of resin so produced inasmuch as the insoluble type is not soluble to any appreciable extent in toluol. acetone, alcohol, ethyl-acetate, carbon tetrachloride, or mineral spirits. with heating. It also is not soluble in molten coumarone-indene resin, or molten terpene resin. The insoluble type of vinyl cyclohexene resin does not melt up to its decomposition point. A less carefully acid washed vinyl cyclohexene, which I also have used, is between 85% and 90% pure.

Whereas the two diverse resins of the insoluble and soluble types have each its individual utility, I have discovered that a more useful product is obtained by polymerizing a mixture of the vinyl cyclohexene, which as shown in the formula is a mixed cyclic and open chain material, with an impure commercial grade of dipentene to produce a soluble, thermoplastic resin. Apparently such resin is in part at least the result of copolymerization, inasmuch as up to a certain percentage of the vinyl cyclohexene only soluble polymers are formed and the resultant resin is obtained in highjected to polymerization with the most active of the acid-reactin metallic halides. It is present in a proportion of about 10% of the whole in sulphate turpentine which is a liquid extracted from the waste produced in the process of making sulphate pulp from the wood of conifers. It is present in a proportion of about 40 in wood spirits of turpentine which is extracted from chips cut from'the stumps of conifers. The commercial" dipentene I use distills within the range of C. to C. (vapor temperature) and has an aniline point by the standard method of aniline point determination of about 28 C. The commercial grade of dipentene is not to be confused with the optically inactive dl-limouene. which is a good starting material for resin-forming polymerization. As separated from the other terpenes of wood turpentine and sulphate turpentine and sold as a commercial grade of dipentene, the dipentene consists chiefly of terpinene and terpinolene with lesser proportions of dl-limonene and other terpenes. I

As polymerized by itself by bringing it into reactive contact with aluminum chloride or an equivalent acid-reacting halide, the commercial dipentene gives an approximately 30% yield of point (ball and ring) of about 80 C. By mixing commercial dipentene with vinyl cyclohexene a resin of higher softening point than is obtainable from the dipentene by itself is obtained in a yield much greater than that obtained without inclusibn of the vinyl cyclohexene. In mixtures of vinyl cyclohexene with commercial dipentene below the maximum permissible proportion of the vinyl cyclohexene, approximately all of the vinyl cyclohexene which is included partakes in the formation of soluble thermoplastic resin without any substantial formation of insoluble polymers.

As a general procedure the vinyl cyclohexene which has been subjected to a purification treatment,'such as the one above described, is mixed with the dipentene and with an organic diluent which is substantially inert to polymerization with the vinyl cyclohexene and the terpene, and is brought into reactive contact with an acidreacting metal halide polymerization catalyst, such as anhydrous aluminum chloride, aluminum bromide, stannic chloride, titanium tetrachloride, antimony pentachloride, ferric chloride and the corresponding bromides of these latter metals, aluminum chloride and aluminum bromide being 'pref'erred. During the progress of the polymerization reaction, the reaction temperature is maintained within a range which desirably is suitable for relatively rapid polymerization without reaction surge, such as a temperature within the approximate range of C to 80 C., a temperature within the range of about 35 C. to 60 C. being considered optimum from the viewpoints of reaction speed and ease of temperature control. Upon the completion of catalyst addition, which desirably is effected without such rapidity as to cause a surge, agitation of the reaction mixture is continued for a substantial period of time completely to polymerize the vinyl cyclohexene and the dipentene.

To remove the catalyst at the end of the polymerization treatment two standard recovery methods may be employed. In accordance with one such procedure the mixture is drowned with a water solution of hydrochloric or sulphuric acid, and is then water washed and neutralized with a water solution of sodium carbonate. The washed solution is then warmed to 260 C. and is allowed to settle until a clear resin solution is obtained. Such resin solution is distilled, desirably at a still temperature of about 210 C., and is then steam distilled at still temperatures within the range of about 210 C. to 260 C. until a resin of the desired melting point remains as a residue.

The other method of removing catalyst and recovering solid resin tends to give a somewhat lighter color than the method described above In accordance with this latter procedure the polymerization mixture is allowed to settle until the metal halide sludge separates out, which separation is complete within about one hour to twenty-four hours. The solution is decanted oil, the sludge is washed with a suitable organic solvent, such as refined solvent naphtha, and the washings are added to the resin solution. The combined resin solution thus obtained is clear, but is deep red in color due to the retention of a 4v soluble complex of the metal halide. This clear but highly colored solution is purified by refluxing it at still temperature of about 140 C. to 150 C. with fuller's earth having but slight acidity, which is not of necessity dry, and slacked lime for a period of three hours. During this I hard terpene resin polymers having a softening treatment hydrochloric acid is driven off and the original soluble aluminum chloride complex comes down as a precipitate. An appropriate quantity of clay for use in the reflux purification is about 7.5% of the total weight of vinyl cyclohexene and alpha-pinene and a quantity of lime equal to the weight of the clay desirably is used. As low as 5% clay and lime may be used and as much may be used as will not interfere with the refluxing. Up to as much as 15% to 20% each of clay and lime is usable. After refluxing, the resin solution is filtered and a clear light yellow resin solution is obtained, one of the common commercial filter aids desirably being used during the filtering. This resin solution is then steam distilled, desirably at still temperatures of about 210 C. to 260 C., until solid resin of the desired melting point remains as a residue.

The above recovery procedure results in the production of a resin of particularly light color, but does so at the sacrifice of a small proportion of the resin yield which is retained in the sludge initially separated from the resin solution. This proportion of the resin carried down with the sludge may largely be recovered by drowning the sludge with a 5% water solution of hydrochloric acid or sulphuric acid, then agitating the resin with an organic solvent, such as distilled solvent naphtha, and distilling off the solvent. This leads to recovery of entrapped resin which is of darker color than that obtained by steam distillation of the resin solution.

It has been noted that the mixture of vinyl cyclohexene and commercial dipentene is diluted with an organic solvent diluent inert to polymerization under the conditions of the process. That diluent preferably is one of the. low aniline point organic solvents which is inert in the process, as for example one of the aromatic hydrocarbon solvents which have no unsaturation outside the benzene ring, such as benzol, toluol, xylol, refined .solvent naphtha and ethyl benzene. or one of the chlorinated aromatic solvents, such as chlorobenzol. Regardless of the specific solvent which is used, most desirably it is included in a quantity not substantially less than 30% the total reaction liquid in order to maintain activity as polymer formation proceeds. It can be included in any greater quantity subject to the practical consideration that increased volume of diluent tends to slow the reaction and to increase the reaction time, and also to require that an increased quantity of catalyst be used in order to make reactive contact with the polymerizable vinyl cyclohexene and dipentene. Also it uneconomical to use and distill off more diluent than performs a useful purpose during the polymerization reaction. As a practical consideration I prefer to include the diluent in no more than about of the total volume of the reaction mixture.

I have found that in using anhydrous aluminum chloride or aluminum bromide as the polymerization catalyst as little as 3% by weight of such catalyst with respect to the combined weight of the vinyl cyclohexene and the dipentene is sufllcient to effect complete polymerization, and

even less than 3% may usefully be employed.

I 8% to 18% the weight of the combined vinyl cyclohexene and dipentene in accordance with the other conditions of the process. Quantities of those catalysts over 25% effect no appreciable shortening in the time required for the polymerization reaction even when conduct of the polymerization at low temperature indicates the use of a relatively large proportion of catalyst, unless a particularly great volume of diluent also be used. polymerizable constituents of a reaction mixture the other metal halide catalysts of the Friedel Crafts type which have been noted above can usefully be proportioned to the above preferred quantities of anhydrous aluminum chloride and aluminum bromide. In substituting aluminum bromide and the other metal halide catalysts for the aluminum chloride, the optimum proportion of catalyst to the polymerizable content of the reaction mixture is desirably increased or decreased with respect to the quantity of aluminum chloride used in proportion as the molecular weight of that particular catalyst is greater or less than that of aluminum chloride.

It has been noted above that in subjecting a mixture of vinyl cyclohexene and commercial dipentene to polymerization the vinyl cyclohexene functions in the mixture to raise the melting point and yield of the resin which may be recovered. It is to be noted that this function is performed down to the least proportion of vinyl cyclohexene which gives a perceptible increase. That minimum proportion is below 15% of vinyl cyclohexene in the mixture of that material with the dipentene, if in fact there is any proportion which may be considered as an absolute minimum exerting no measurable eifect on the product resin. For purposes of practical definition of the point at which the effect of including vinyl cyclohexene becomes negligible, I give 10% as a minimum. In seeking to obtain resin of particularly high melting point the proportion of vinyl cyclohexene to dipentene can be increased for the production of high melting thermoplastic resin up to a point at which the proportion of insoluble polymers renders further increase in the proportion of the vinyl cyclohexene uneconomical. I have found that the best average results both as to the melting point of the thermoplastic resin which is produced and the yield of such thermoplastic resin are obtained when the vinyl cyclohexene constitutes about 25% to45% of the polymerizable mixture, there being an appreciable production of insoluble resin when equality in the weights of the two ingredients is approached with rapid increase above that point.

In proportioning the catalyst to the My starting material for polymerization thus comprises a mixture of commercial dipentene and vinyl cyclohexene in which the vinyl cyclohexene is included in a proportion of from 10% to 50% of the total blend and most desirably in a proportion of from 25 to 45% of the blend in order to obtain maximum inclusion of vinyl cyclohexene in the resin polymers without forming insoluble polymers, the proportions being by weight.

The following will exemplify the method of my invention.

Example 1 In this example the vinyl cyclohexene forming an element of the blended starting material was acid washed and about 90% pure figured on the basis of total unsaturation in accordance with its bromine number. The dipentene was a commercial grade obtained by acid treatment of wood turpentine, and distilled over within the range of 170 C. to 180 C. (vapor temperature). The dipentene when subjected to polymerization by itself under the influence of anhydrous aluminum chloride gave a 30% yield of 80 C. (ball and ring) softening point terpene resin. The reaction mixture was made up by blending 100 cc. (83 gm.) of vinyl cyclohexene and 140 cc. (120 gm.) of the dipentene with 300 cc. of toluol. 20 gm. of anhydrous aluminum chloride was added as catalyst and was brought with agitation into reactive contact with the vinyl cyclohexene and dipentene of the reaction liquid. The catalyst was added to the reaction mixture in small increments during a period of 1 hour and after addition of the catalyst was complete the reaction mixture was stirred for an additional period of 2 hours. During the reaction the temperature was held by circulation of heat abstracting liquid tlsirough cooling jackets to a range of 35 C. to 4 C.

At the end of the polymerization treatment the reaction mixture was warmed to 60 C., was allowed to settle and a clear solution was decanted away from the sludge. That sludge was drowned with a 5 water solution of hydrochloric acid and was agitated with distilled solvent naphtha. The solution from the sludge was added to the original solution. This entire resin solution was refluxed with clay and lime and was filtered. The filtered solution was distilled to 210 C. (still temperature) and was steam distilled at a still temperature of from 210 C. to 260 C. until a residue of solid resin was obtained.

The resin recovered by distillation was in a yield of 188 gm. (92.4%) the combined weight of the vinyl cyclohexene and commercial dipentene of thermoplastic soluble resin having a softening point of 113 C. (ball and ring) and a color 9 on the Gardner scale. This latter resin when dissolved in an equal proportion by weight of mineral spirits showed no cloud down to a temperature of 0 C. No insoluble resin was formed.

Example 2 In this example the vinyl cyclohexene and the dipentene was about pure and the dipentene was of the same grade as in Example 1. They were, however, blended in the proportion of 122 cc. gm.) of vinyl cyclohexene and 118 cc. (101 gm.) of dipentene. This reactive blend was mixed with 300 cc. of toluol to form thereaction mixture. To this reaction liquid 20 gm. of anhydrous aluminum chloride was added as catalyst and was brought with agitation into reactive contact with the vinyl cyclohexene and dipentene of the reaction liquid. As in the foregoing example, the aluminum chloride was added to the reaction mixture in small increments during a period of 1 hour, and after addition of the catalyst was complete the reaction mixture was stirred for an additional period of 2 hours. During the reaction the temperature was held by circulation of heat abstracting liquid through cooling jackets to a range of 35 C. to 45 C. Insoluble resin in the amount of 8 gm. was formed.

The resin recovery was identical with that of Example 1.

The resin recovered by distillation was 169.4 gm. (83.9%) of thermoplastic soluble resin having a softening point of 103 C. (ball and ring) and a color 8 on the Gardner scale. This latter resin when dissolved in an equal proportion by weight of mineral spirits showed no cloud down to a temperature of 0 C.

'7 It. may be noted that the foregoing example exemplified the approximate maximum propor- A starting material was made by mixing vinyl cyclohexene and dipentene of the same grades used in Example 2. The mixture was made up of 48 cc. (42 gm.) of the vinyl cyclohexene and 215 cc.(182 gm.) of the dipentene. This liquid was mixed with 300 cc. of toluol. 20 gm. of anhydrous aluminum chloride was added during a period of 1 hour and was, brought with agitation into reactive contact with the vinyl cyclohexene and dipentene of the reaction liquid. The reaction mixture was stirred for an additional period of 2 hours. During the reaction the temperature was held within the range of 40 C. to 45 C.

The recovery procedure was identical with that of Example 1.

The resin recovered by distillation was a thermoplastic soluble resin having a softening point (ball and ring) of 90 C. and a color 8 on the Gardner scale. The yield of solid thermoplastic resin, no insoluble resin being formed, was 172 gm. (77%) the weight of the combined vinyl cyclohexene and dipentene. The resin when dissolved in an equal proportion by weight of mineral spirits showed no cloud down to a temperature of C.

The foregoing exemplifies the-fact that a relatively small proportion of vinyl cyclohexene when blended with a commercial dipentene materially affects the results of the polymerization. The result of including with the dipentene only a small proportion of the vinyl cyclohexene is thereforeto obtain an appreciably increased yield of a resin of appreciably higher softening point with respect to the yield and Softening point obtained by polymerizing the dipentene alone.

Example 4 In this example vinyl cyclohexene and dipentene of the same grades as those used in Example Nos. 2 and 3 were mixed. The reaction mixture was made up by mixing 140 cc. (116 gm.) of vinyl cyclohexene and 140 cc. (120 gm.) of the dipentene with 300 cc. of toluol and 32 gm. (13.6%) aluminum chloride was added. The catalyst was brought with agitation into reactive contact with the vinyl cyclohexene and dipentene of the reaction liquid. The catalyst was added to the reaction mixture in small increments during a period of 1 hour and after addition of the catalyst was completed the reaction mixture was stirred for an additional period of 8 hours. During the reaction the temperature was held by circulation of heat abstracting liquid through cooling jackets to a range of 20 C. to 30 C. Some insoluble resin was formed.

At the end of the polymerization treatment the reaction mixture was warmed to 60 C. was allowed to settle and a clear solution was decanted. Because of the lower temperature at which the polymerization was conducted there was a greater precipitation of sludge than resulted from the polymerization in Examples 1, 2 and 3. This sludge was drowned with a water solution of hydrochloric acid and was agitated with distilled solvent naphtha. The solution from the sludge was added to the original decanted solution. The entire resin solution was refluxed with clay and lime, was filtered and the filtered solution was distilled at a still temperature of 210 C. and was steam distilled at a still temperature from 210 C. to 260 C. until a residue of solid resin was obtained.

The resin recovered by distillation included 10 gm. of insoluble resin and 186 gm. of thermoplastic soluble resin having a softening point of 117 C. (ball and ring) and was color CA; on the Gardner scale. This latter resin when dissolved in an equal proportion by weight of mineral spirits showed no cloud down to a temperature of 0 C.

Example 5 portion of cc. (83 gm.) of vinyl cyclohexene,

and 140 cc. gm.) of dipentene and were mixed with 300 cc. of toluol to form the reaction mixture. To this reaction liquid 24 gm. (12%) of anhydrous aluminum chloride was added as the catalyst and was brought with agitation into reactive contact with the vinyl cyclohexene and dipentene of the reaction liquid.

The polymerization procedure and recovery procedure were identical with those described in Example 4.

The resin recovered by distillation was a thermoplastic soluble resin having a softening point of 120 C. (ball and ring) and a color 8 on the Gardner scale. The yield was 182 gm. (89%) of resin which when dissolved in an equal proportion by weight of mineral spirits showed no cloud down to a temperature of 0 C. No insoluble resin was formed.

Example 6 Vinyl cyclohexene and dipentene of the same grades as in Examples 2 and 3 were mixed in the proportion of 48 cc. (44 gm.) of vinyl cyclohexene and 215 cc. (182 gm.) of dipentene and were mixed with 300 cc. of toluol to form the reaction mixture. To this reaction liquid 28 gm. (13.6%) of anhydrous aluminum chloride was added as the catalyst and was brought with agitation into reactive contact with the vinyl cyclohexene and dipentene of the reaction liquid.

The polymerization procedure was identical with that described in Example 4. Because of the relatively great proportion of dipentene included in the reaction liquid the precipitation of sludge was much less than in Examples 4 and 5. The sludge was, however, washed in order to insure that all recoverable resin was included in the yield.

The recovery procedure was identical with that of Example 1.

The resin recovered by distillation was a thermoplastic soluble resin having a softening point of 84 C. (ball and ring) and was color 9 on the Gardner scale. The yield of solid thermoplastic resin, no insoluble resin being formed, was 178 gm. (78%) the weight of the combined vinyl cyclohexene and dipentene. The resin when dissolved in an equal proportion by weight of mineral spirits showed no cloud down to a temperature of 0 C.

The foregoing Examples 4, 5 and 6 illustrate the fact that with lower reaction temperature it is desirable to use an increased quantity of catalyst and to continue the polymerization period for an extended length of time in order to secure results close to those obtained at higher temperature. As noted above, the vinyl cyclohexene is relatively sluggish in its response to polymerization promoting stimuli. It will be noted that in Examples 4, and 6 the lower temperature of polymerization gives a resin of somewhat higher softening point, obtained in slightly decreased yield than in analogous Examples 2, 1 and 3. At the expense of an even more extended reaction period the polymerization at the lower temperature gives an almost equal yield of resin as compared with the higher temperature, while obtaining the benefit of higher softening point.

Using the same proportions of vinyl cyclohexene and dipentene as in Examples 4, 5 and 6 polymerization was conducted at a temperature within the range of 10 C. to C. In each instance catalyst in a quantity equal to 18% the weight of the combined vinyl cyclohexene and dipentene was used and the polymerization period after addition of the catalyst was extended to 18 hou s. The result was to obtain yields approximately identical with those of Examples 4, 5 and 6 with an increase of about 4 C. in the softening point of the resin.

Duplication of the procedures given above but using aluminum bromide instead of aluminum chloride as catalyst gave almost identical results. The other acid-reacting metal halides are usable in the process, Even when employed in increased quantity they give lower yields of resin.

The resin produced from a mixed vinyl cyclohexene and commercial dipentene starting material corresponds in most particulars to terpene resins. In all proportioning of the two ingredients of the starting material the resin is usable in all ways in which a straight terpene resin is usable, as for example in coating compositions, hot melt coatings, adhesives, rubber compounding, chewing gum bases and the like. Guides to satisfactory procedure in such uses are found in patents to Frank W. Corkery and Samuel G. Burroughs No. 2,320,717; No. 2,319,389; No. 2,320,718; and No. 2,357,811.

Although terpene resins as carefully produced are considered to possess good color stability, the resin produced by polymerizing a mixture of vinyl cyclohexene and dipentene exhibits higher resistance to color development than do the other terpene resins, including straight beta-pinene resin.

It has been noted above that it is desirable in the process to use an inert solvent diluent of low aniline point. I have found it preferable to use such solvent diluents as have an A. S. T. M. D611-46T aniline point no higher than 35 C. Most of the commercially desirable solvents of this sort have aniline points by the above determination falling within the range of about 15 C. to 35 C.

Throughout the specification aniline point, where not specifically qualified by the method of its determination, is to be understood as determined by the A. S. T. M. D611-46T. aniline point method. Where not specifically qualified in the specification, softening point is to be understood as determined by the ball and ring method of softening point determination. Where not specifically qualified in the specification, distillation temperatures are to be understood as taken at 750 mm. of mercury. Where not specifically qualified proportions are to be understood as proportions by weight. In any example in which the formation of insoluble resin is not noted, no insoluble resin was formed.

In my companion application Serial No, 45,783,

filed August 23, 1948, of even date herewith, I have disclosed the polymerization of mixtures of turpentines which contain dipentene with the defined cyclic mono-olefine in which a vinyl group is substituted. Herein the disclosure relates to the polymerization of a mixture of dipentene as such with that defined cyclic mono-olefine, 1- vinyl cyclohexene-3, designated through the specification simply as vinyl cyclohexene, and to the resin produced'by that polymerization.

I claim as my invention:

1. The method of producing hard resin polymers by bringing a mixture of 1-vinyl cyclohexene-3 (cyclic dimer of butadiene) and commercial dipentene in a proportion of vinyl cyclohexene equal to from 10% to 50% the weight of the blend into reactive contact with an acid-reacting metal halide polymerization catalyst in the presence of an inert solvent diluent for the polymers of the said vinyl cyclohexene and the said dipentene, to form hard resin polymers of vinyl cyclohexene and the dipentene in solution, and

recovering the resin polymers so formed.

2. The method of producing hard resin polymers by bringing a mixture of l-vinyl cyclohexene-3 (cyclic dimer of butadiene) and commercial dipentene in a proportion of vinyl cyclohexene equal to from 25% to 45% the weight of the blend into reactive contact with an acid-reacting metal halide polymerization catalyst in the presence of an inert solvent diluent for the polymers of the said vinyl cyclohexene and the said dipentene, to form hard resin polymers of vinyl cyclohexene and the dipentene in solution, and recovering the resin polymers so formed.

3. The method of producing hard resin polymers by bringing a mixture of l-vinyl cyclohexene-3 (cyclic dimer of butadiene) and commercial dipentene in a proportion of vinyl cyclohexene equal to from 10% to 50% the weight of the blend into reactive contact with aluminum chloride polymerization catalyst in the presence of an inert solvent diluent for the polymers of the said vinyl cyclohexene and the said dipentene, to form hard resin polymers of vinyl cyclohexene and the dipentene in solution, and recovering the resin polymers so formed.

4. The method of producing hard resin polymers by bringing a mixture of l-vinyl cyclohexene-3 (cyclic dimer of butadiene) and commercial dipentene in a proportion of vinyl cyclohexene equal to from 10% to 50% the weight of the blend into reactive contact with aluminum bromide polymerization catalyst in the presence of an inert solvent diluent for the polymers of the said vinyl cyclohexene and the said dipentene to form hard resin polymers of vinyl cyclohexene and the dipentene in solution, and recovering the resin polymers so formed.

5. The method of producing hard resin polymers by bringing a mixture of l-vinyl cyclohexene-3 (cyclic dimer of butadiene) and commercial dipentene in a proportion of vinyl cyclohexene equal to form 25% to 45% the weight of the blend into reactive contact with aluminum chloride polymerization catalyst in the presence of an inert solvent diluent for the polymers of the said vinyl cyclohexene and the said dipentene to form hard resin polymers of vinyl cyclohexene and the dipentene in solution, and recovering the resin polymers so formed.

6. The method of producing hard resin polymers by bringing a mixture of l-vinyl cyclohexene-3 (cyclic dimer of butadiene) and commer- I! 12 cial dipentene in a, proportion of vinyl cyclohex- UNITED STATES PATENTS ene equal to from 25% to 45% the wei Number Name Date the blend into reactive contact with aluminum 2346.791 Rummelsburg 18 19 bromide polymerization catalyst in the presence 2,349,210 Traylor 19 of an inert solvent diluent for the polymers of 5 2,383,084 gggg Aug 1945 the said vinyl cyclohexene and the said dipentene 2,401,414 Doumam Jug: 1946 to form hard resin polymers of vinyl cyclohex- 2,475,234 Gleason July 1949 one and the dipentene in solution, and recover- 2,487,398 Rummelsbur fi 5 949 ing the resin polymers so formed.

7. The resin produced by the process of claim 1. 1o EIGN PATENTS Number Country Date SAMUEL G. BURROUGHS. 614,781 Great Britain Dec. 22, 1948 REFERENCES CITED OTHER REFERENCES 5 Laitinen et 9.1.: Ind. 81 Engr. Chem, Anal. Ed., 2; h ggf i g mud in the vol. 17, pp. 769-772 (December 1945). 

1. THE METHOD OF PRODUCING HARD RESIN POLYMERS BY BRINGING A MIXTURE OF 1-VINYL CYCLOHEXENE-3 (CYCLIC DIMER OF BUTADINE) AND COMMERCIAL DIPENTENE IN A PROPORTION OF VINYL CYCLOHEX ENE EQUAL TO FORM 10% TO 50% THE WEIGHT OF THE BLEND INTO REACTIVE CONTACT WITH AN ACID-REACTING METAL HALIDE POLYMERIZATION CATALYST IN THE PRESENCE OF AN INERT SOLVENT DILUENT FOR THE POLYMERS OF THE SAID VINYL CYCLOHEXANE AND THE SAID DIPENTENE, TO FORM HARD RESIN POLYMERS OF VINYL CYCLOHEXENE AND THE DIPENTENE IN SOLUTION, AND RECOVERING THE RESIN POLYMERS SO FORMED. 